Key parameters at a glance

A radius of 2.10 Earth radii
A mass of 135.00 Earth masses
Surface gravity around 30.61 g
An orbital period of 7.877 days
Semi-major axis 0.0637 AU
Equilibrium temperature 553 K (280 °C)
Distance from Earth 1,048.73 light-years
Earth Similarity Index 0.395
Travel time at Voyager 1 speed 18,494,327 years
Almost certainly tidally locked to its host star given the close orbit

2 siblings around Kepler-52

Kepler-52 b shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-52 b this	Sub-Neptune	2.10	135.00	7.877	553	2012
Kepler-52 c	Super-Earth	1.84	45.40	16.385	433	2012
Kepler-52 d	Super-Earth	1.95	88.88	36.445	332	2014

Kepler-52 b Planet Profile

Physical Specs

Radius

2.10 R⊕

Radius (Jupiter)

0.187 R♃

Mass

135.00 M⊕

Mass (Jupiter)

0.425 M♃

Density

3.35 g/cm³

Surface Gravity

30.61 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.395

HZ Position Inner

Controversial No

Discovery

Year 2012

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1818of 1978

top 91.9%

This planet

2.10R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-1529 b 2.10 R⊕ Kepler-360 c 2.10 R⊕ TOI-5734 b 2.10 R⊕

Metric	Earth	Kepler-52 b	Jupiter
Radius (R⊕)	1.00	2.10	11.21
Mass (M⊕)	1.00	135.00	317.83
Density (g/cm³)	5.51	3.35	1.33
Surface Gravity (g)	1.00	30.61	2.53
Insolation (S⊕)	1.00	22.72	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	135.000 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 399825554

Gaia DR2

Gaia DR2 2133589776693414016

Gaia DR3

Gaia DR3 2133589776693414016

System

Kepler-52

Percentile among Sub-Neptune cohort

Radius 2.100 R⊕ · percentile 7 / cohort 1978

Mass 135.000 M⊕ · percentile 99 / cohort 1978

Orbital period 7.88 d · percentile 25 / cohort 1946

Distance 321.54 pc · percentile 37 / cohort 1975

ESI 0.395 · percentile 51 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

7.877 days

Semi-major axis

0.0637 AU

Eccentricity

0.000

Inclination

89.92 °

Year Length

A year here lasts approximately 7.88 Earth days (2.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0637 AU.

Transit Fingerprint

Depth

0.146 %

Duration

2.422 h

Impact parameter b

0.040

Rp / R★

0.036980

Transit midpoint (BJD)

2,455,009.3769

Photometric dip

Transit produces a flux drop of 1,462 ppm lasting ≈ 2.42 h.

Extended Orbital Architecture

Planet / star radius ratio

0.036980

Semi-major axis / stellar radius

29.800

Impact parameter (b)

0.040

Transit mid-time (BJD)

2,455,009.3769

Angular separation (arcsec)

0.19800

Eq. Temperature

553K

(280 °C)

Insolation (S⊕)

22.72

Earth = 1.00

Earth Similarity (ESI)

0.395

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

Steffen et al. 2013

Instrument

Kepler CCD Array

Publication

2013-01

Observation locale

Space

Discovery cohort

Planets confirmed in 2012 at Kepler (12 shown).

Kepler-54 c · Rocky Terrestrial Kepler-49 c · Sub-Neptune Kepler-55 b · Sub-Neptune Kepler-49 b · Sub-Neptune Kepler-81 c · Sub-Neptune Kepler-55 c · Sub-Neptune Kepler-52 c · Super-Earth Kepler-83 c · Sub-Neptune Kepler-32 d · Sub-Neptune Kepler-83 b · Sub-Neptune Kepler-54 b · Sub-Neptune Kepler-80 c · Sub-Neptune

Host System: Kepler-52

Spectral Class

M-type red dwarf

Effective Temperature

4,075 K — cooler than the Sun (5,778 K)

Estimated Age

1.01 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.520 R☉

Stellar Mass

0.540 M☉

Metallicity [Fe/H]

0.00

Extended Stellar Properties

Surface gravity (log g)

4.740 dex

Stellar density

3.440 g/cm³

Metallicity ratio

[Fe/H]

Distance

321.54 parsec

Light-years 1,048.73 ly

V-band magnitude

15.51 mag

Voyager-speed travel 18,494,327 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

3.081 mas

Total Proper Motion

4.207 mas/yr

PM Right Ascension

-3.98 mas/yr

PM Declination

1.38 mas/yr

Galactic Cartesian (pc)

x = 0.185 · y = -0.616 · z = 0.766

Equatorial (J2000)

RA 286.73802° · Dec 49.97574°

Galactic ℓ, b

80.478° · 18.087°

Ecliptic λ, β

305.415° · 71.362°

HTM-20 index

364710180